WO2014126048A1

WO2014126048A1 - Pneumatic tire

Info

Publication number: WO2014126048A1
Application number: PCT/JP2014/053054
Authority: WO
Inventors: 広樹遠藤
Original assignee: 横浜ゴム株式会社
Priority date: 2013-02-12
Filing date: 2014-02-10
Publication date: 2014-08-21
Also published as: EP2957437A4; US20150375572A1; EP2957437A1; RU2015138975A; JP2014151811A; CN105026184A

Abstract

Provided is a pneumatic tire in which on-ice braking performance and pin dropout prevention performance are improved in a balanced manner. The number of driven-in stud pins (24) in the shoulder region (TS) is 1.5 to 2.5 times the number of driven-in stud pins (24) in the center region (TC), and the protrusion amount of the stud pins (24) in the shoulder region (TS) is 1.2 to 2.0 times the protrusion amount of the stud pins (24) in the center region (TC).

Description

Pneumatic tire

The present invention relates to a pneumatic tire in which stud pins are embedded in a tread surface.

Conventionally, a pneumatic tire in which stud pins are embedded in a tread surface is known (for example, see Patent Document 1). Patent Document 1 discloses that on-ice braking performance and the like can be improved by controlling the number of stud pin driving holes and hence the number of stud pin driving.

JP 2012-183554 A

However, it is unclear whether the braking performance on ice and the anti-pinning performance can be improved in a well-balanced manner only by controlling the number of stud pins driven in.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a pneumatic tire in which braking performance on ice and anti-pinning performance are improved in a well-balanced manner.

In order to solve the above problems, in the pneumatic tire according to the present invention, a land portion is defined by a plurality of inclined grooves inclined with respect to the tire circumferential direction, and a sipe is provided in at least one of the land portions. The stud pin is embedded in at least one of the land portions. Here, an area of 50% of the tire ground contact width centered on the tire equator plane is set as a center area, and each area up to the ground contact end in the tire width direction on both sides of the center area is set as a shoulder area. . Under such a premise, the number of stud pins driven in the shoulder region is 1.5 to 2.5 times the number of stud pins driven in the center region. The average protrusion amount of the stud pin in the shoulder region is 1.2 to 2.0 times the average protrusion amount of the stud pin in the center region.

In the pneumatic tire according to the present invention, the number of stud pins driven in the shoulder region with respect to the center region and the average protrusion amount of the stud pins are within a predetermined range. As a result, the braking performance on ice and the anti-pinning performance can be improved with a good balance.

FIG. 1 is a developed plan view showing an example of a tread portion of a pneumatic tire according to an embodiment of the present invention. FIG. 2 is a cross-sectional view taken along the line AA ′ of FIG. 1, showing an example of a stud pin embedded state in the pneumatic tire according to the embodiment of the present invention.

Hereinafter, embodiments of the pneumatic tire according to the present invention (basic modes and additional modes 1 to 3 shown below) will be described in detail with reference to the drawings. Note that these embodiments do not limit the present invention. In addition, the constituent elements of the above embodiment include those that can be easily replaced by those skilled in the art, or those that are substantially the same. Furthermore, various forms included in the above-described embodiment can be arbitrarily combined within a range obvious to those skilled in the art.

[Basic form]
Below, the basic form is demonstrated about the pneumatic tire which concerns on this invention. In the following description, the tire radial direction means a direction orthogonal to the rotational axis of the pneumatic tire, the tire radial inner side is the side toward the rotational axis in the tire radial direction, and the tire radial outer side is in the tire radial direction. The side away from the rotation axis. The tire circumferential direction refers to a circumferential direction with the rotation axis as a central axis. Further, the tire width direction refers to a direction parallel to the rotation axis, the inner side in the tire width direction is the side toward the tire equatorial plane CL in the tire width direction, and the outer side in the tire width direction is the tire equatorial plane CL in the tire width direction. The side away from. The tire equatorial plane CL is a plane that is orthogonal to the rotational axis of the pneumatic tire and passes through the center of the tire width of the pneumatic tire.

FIG. 1 is a plan development view showing an example of a tread portion of a pneumatic tire according to an embodiment of the present invention. The tread portion shown in the figure is made of a rubber material (tread rubber), and is exposed at the outermost side in the tire radial direction of the pneumatic tire, and the surface thereof is the contour of the pneumatic tire. The surface of the tread portion is formed as a tread surface 10 that is a surface that comes into contact with the road surface when a vehicle (not shown) equipped with a pneumatic tire travels.

The tread surface 10 is provided with a plurality of inclined grooves 12 that are inclined with respect to both the tire circumferential direction and the tire width direction. As the inclined groove 12, various types can be adopted, and for example, as shown in FIG. 1, the width changes in the extending direction of the groove, and the inclined groove 12 branches in the middle of the extending.

Although not shown in FIG. 1, the tread surface 10 may optionally include a plurality of circumferential grooves extending in the tire circumferential direction. Various types of circumferential grooves can also be employed, and examples thereof include those in which the width does not change in the extending direction of the grooves.

Similarly, although not shown in FIG. 1, the tread surface 10 can optionally include a plurality of widthwise grooves extending in the tire width direction. Various types can be adopted for the width direction groove, for example, one whose width changes in the extending direction.

The plurality of inclined grooves 12 as a whole can be formed in a shape that continues in the tire circumferential direction via a circumferential groove not shown in FIG. 1, and of course, continues in the tire circumferential direction without passing through the circumferential groove. It can also be a zigzag shape. In this way, when the plurality of inclined grooves 12 form a zigzag shape as a whole, and particularly when the angle formed by the tire circumferential direction of each inclined groove 12 is small, the zigzag inclined groove group is a tire. It can be regarded as a circumferential groove continuous in the circumferential direction. Therefore, in the present embodiment, it is not assumed that the circumferential grooves continuous in the tire circumferential direction are positively excluded.

In addition, the tread surface 10 is provided with sipes 22 in at least one of the land portions, as shown in FIG. The sipe 22 may extend linearly in the tire width direction, or may have a zigzag shape, a sine wave shape, a triangular wave shape, a rectangular wave shape or the like that has an amplitude in the tire circumferential direction and extends in the tire width direction. It may be. Moreover, the sipe 22 may extend intermittently in the tire width direction within one land portion 20.

Thus, the tread surface 10 of the pneumatic tire according to the present embodiment has the inclined grooves 12 and can optionally form the circumferential grooves and the width grooves. And the predetermined tread pattern is formed in the tread surface 10 by forming the sipe 22 in at least one of the land parts 20 defined by these grooves.

The stud pin 24 is embedded in at least one of the land portions 20, for example, the location shown in FIG. 1 on the tread surface 10 having the tread pattern. The stud pins 24 are embedded at a constant pitch in the tire circumferential direction at a predetermined position in the tire width direction.

Under the premise as described above, in the present embodiment, as shown in FIG. 1, an area of 50% of the tire contact width centered on the tire equatorial plane CL is defined as the center area TC, and the center area TC Regions on both outer sides in the tire width direction up to the contact point E are defined as shoulder regions TS.

In the present embodiment, as shown in FIG. 1, the number of stud pins 24 driven in the shoulder region TS (the number of shoulders) is 1.5, which is the number of stud pins 24 driven in the center region TC (the number of centers). Double to 2.5 times.

When a certain number of stud pins 24 are embedded in one tire with the same amount of protrusion from the tread surface, when embedded more in the shoulder region TS than in the center region TC, it is caused by the scratching effect on ice. The effect of improving the braking performance on ice is remarkable. Therefore, as described above, by setting the number of shoulders to be 1.5 times the number of centers or more, a sufficient scratching effect on ice is ensured in the shoulder region TS that is particularly likely to affect braking performance on ice, and the entire tire As a result, the braking performance on ice can be improved efficiently.

In addition, when the tire rolls, the stud pin 24 is more easily removed in the center region TC than in the shoulder region TS. For this reason, as described above, by setting the number of shoulders to be 1.5 times the number of centers or more, the number of stud pins is reduced in the center region TC, which tends to affect the anti-pinning performance, thereby suppressing pin removal. In addition, the anti-pinning performance can be efficiently improved as a whole tire.

On the other hand, when a certain number of stud pins 24 are embedded in one tire with the same amount of protrusion from the tread surface, the stud pins 24 are embedded excessively in the shoulder region TS with respect to the center region TC. In such a case, due to the reduction in the number of stud pins 24 in the center region TC, the braking performance on ice due to the scratching effect on ice cannot be sufficiently obtained. For this reason, as described above, by making the number of shoulders 2.5 times or less the number of centers, while obtaining a scratching effect on ice in the shoulder region TS, this effect can be sufficiently obtained in the center region TC, The braking performance on ice can be improved efficiently as a whole tire.

Next, on the tread surface of the present embodiment, the average protrusion amount (shoulder average protrusion amount) of the stud pin 24 in the shoulder region TS is equal to the average protrusion amount (center average protrusion amount) of the stud pin 24 in the center region TC. From 1.2 times to 2.0 times. Here, the protruding amount of the stud pin 24 is the maximum dimension in the tire radial direction of the stud pin measured from the tread surface in the state where the hole in which the stud pin 24 is embedded is not formed at the embedded position of the stud pin. Say. In addition, the average protrusion amount refers to an average value of the protrusion amount of the stud pin 24 in each region (center region TC and shoulder region TS).

FIG. 2 is a cross-sectional view taken along the line AA ′ of FIG. 1, showing an example of a buried stud pin in the pneumatic tire according to the embodiment of the present invention. In the example shown in FIG. 2, the ratio of the average protrusion amount of the stud pin 24 formed in the shoulder region TS and the average protrusion amount of the stud pin 24 formed in the center region TC (shoulder region TS / center region TC) is 1.2 to 2.0.

When the stud pin 24 is embedded in both the center region TC and the shoulder region TS with the same average protrusion amount and the same other conditions (for example, the number of driving), the shoulder region is more than the center region TS. In TS, the effect of improving braking performance on ice due to the scratching effect on ice appears remarkably. Further, the greater the average protrusion amount, the deeper the stud pin 24 digs into the ice, so the scratching effect is greater. For this reason, as described above, by making the shoulder average protrusion amount 1.2 times or more of the center average protrusion amount, a sufficient scratching effect on ice is ensured particularly in the shoulder region TS that is likely to affect the braking performance on ice. In addition, the braking performance on ice can be efficiently improved as a whole tire.

In addition, when the tire rolls, the stud pin 24 is more easily removed in the center region TC than in the shoulder region TS. For this reason, as described above, by setting the shoulder average protrusion amount to 1.2 times or more of the center average protrusion amount, the average protrusion amount of the stud pin is reduced particularly in the center region TC that easily affects the anti-pinning resistance performance. Thus, pin omission can be suppressed, and the anti-pin omission performance can be efficiently improved as a whole tire.

On the other hand, when the average protrusion amount of the stud pin 24 in the shoulder region TS is excessively increased as compared with the center region TC, the stud pin 24 is easily pulled out in the shoulder region TS, and the anti-pinning resistance performance is improved. Not. Further, when the stud pin 24 comes off in the shoulder region TS, the braking performance on ice is not improved due to the reduction of the scratching effect on ice in the shoulder region TS. For this reason, as described above, by setting the shoulder average protrusion amount to be 2.0 times or less of the center average protrusion amount, the anti-pinning resistance performance and the braking performance on ice can be efficiently improved as a whole tire. .

As described above, in the pneumatic tire according to the present embodiment, the number of stud pins driven and the average protrusion amount are defined in relation to the center region and the shoulder region, respectively. As a result, the braking performance on ice resulting from the scratching effect on ice and the anti-pinning performance can be efficiently improved in a well-balanced manner as a whole tire.

In addition, although not shown in figure, the pneumatic tire of this embodiment shown above has the meridian cross-sectional shape similar to the conventional pneumatic tire. Here, the meridional cross-sectional shape of the pneumatic tire refers to a cross-sectional shape of the pneumatic tire that appears on a plane perpendicular to the tire equatorial plane CL. The pneumatic tire of the present embodiment has a bead portion, a sidewall portion, and a tread portion from the inner side in the tire radial direction toward the outer side in a tire meridional cross-sectional view. And, for example, in the tire meridional section, the pneumatic tire extends from the tread portion to the bead portions on both sides and wound around the pair of bead cores, and on the outer side in the tire radial direction of the carcass layer. A belt layer and a belt reinforcing layer are sequentially formed.

In addition, the pneumatic tire of the present embodiment includes normal manufacturing processes, that is, a tire material mixing process, a tire material processing process, a green tire molding process, a vulcanization process, and an inspection process after vulcanization. It is obtained through the process. When manufacturing the pneumatic tire of the present embodiment, in particular, vulcanization is performed using a mold capable of forming a predetermined tread pattern as shown in FIG. A stud pin is embedded at a predetermined position.

[Additional form]
Next, additional embodiments 1 to 3 that can be optionally implemented with respect to the basic embodiment of the pneumatic tire according to the present invention will be described.

(Additional form 1)
In the basic form, the arrangement density of the sipe 22 in the shoulder region TS (shoulder arrangement density) is 0.4 to 0.8 times the arrangement density (center arrangement density) of the sipe 22 in the center region TC. It is preferred (additional form 1). Here, the arrangement density of the sipes 22 refers to the total length of the sipes 22 per unit area of the land portion 20 in each region (center region TC and shoulder region TS). Note that the sipe length when the sipe is not linear, for example, zigzag, refers to the length measured when the zigzag sipe is stretched to be linear.

By setting the shoulder arrangement density to 0.8 times or less of the center arrangement density, the sipe arrangement density is surely reduced in the shoulder area TS as compared with the center area TC. As a result, the block rigidity can be increased in the shoulder region TS in which more stud pins 24 are disposed with respect to the center region TC, and in particular, the anti-pinning resistance performance in the shoulder region TS can be improved.

On the other hand, as a result of excessively reducing the sipe arrangement density in the shoulder region TS as compared with the center region TC, if the sipe arrangement density required in the shoulder region TS is lower, the edge effect due to the sipe in the shoulder region TS is sufficient. It can no longer be obtained. Therefore, by setting the shoulder arrangement density to 0.4 times or more of the center arrangement density, it is possible to secure the edge effect due to sipes and improve the braking performance on ice, particularly in the shoulder region TS.

(Additional form 2)
In the basic form and the form in which the additional form 1 is added to the basic form, the average depth (shoulder average depth) of the inclined grooves 12 in the shoulder region TS is equal to the average depth (center average) of the inclined grooves 12 in the center region TC. It is preferably 1 mm to 3 mm smaller than (depth) (additional form 2). Here, the depth of the inclined groove 12 refers to the maximum dimension of the inclined groove 12 measured in the tire radial direction from the tread surface 10 when there is no inclined groove 12. The average depth refers to the average value of the depth of the inclined groove 12 in each region (center region TC and shoulder region TS).

By making the shoulder average depth 1 mm or more smaller than the center average depth, the block region is increased in the shoulder region TS in which more stud pins 24 are disposed with respect to the center region TC. The removal performance can be improved.

On the other hand, when the shoulder average depth is excessively reduced as compared with the center average depth, not only the drainage performance in the shoulder region TS is lowered, but also the grooves provided in the tread surface 10 in the shoulder region TS are exposed to snow. The force (snow column shearing force) that tries to cut off the snow column that can be stepped down decreases, and the braking / driving performance on the snow decreases. For this reason, by setting the difference between the shoulder average depth and the center average depth to be 3 mm or less, drainage performance can be ensured particularly by a sufficient groove depth in the shoulder region TS, and the shearing force on snow is not reduced. In addition, braking / driving performance on snow can be ensured.

(Additional form 3)
In the basic form and the form obtained by adding at least one of the additional forms 1 and 2 to the basic form, in the tread development surface in the unloaded state in which the internal pressure of −5% to + 5% of the normal internal pressure is applied, the shoulder region TS The groove area (shoulder groove area) is preferably 0.4 to 0.8 times the groove area (center groove area) in the center region TC (additional form 3). Here, the normal internal pressure means “maximum air pressure” defined by JATMA, the maximum value described in “TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES” defined by TRA, or “INFLATION PRESSURES” defined by ETRTO. Further, the tread development surface refers to a plane regarding the tread portion as shown in FIG. Furthermore, the groove area refers to the area of the groove partition region expressed on the tread development surface.

In the no-load state where the predetermined internal pressure is applied, the shoulder groove area is set to 0.8 times or less of the center groove area, thereby blocking the shoulder region TS in which more stud pins 24 are disposed with respect to the center region TC. The rigidity can be increased, and in particular, the anti-pinning performance in the shoulder region TS can be improved.

On the other hand, if the shoulder groove area is excessively small with respect to the center groove area, not only the drainage performance in the shoulder region TS is lowered, but also the snow column shear force is reduced in the shoulder region TS, and braking / driving on snow is performed. Performance decreases. For this reason, by making the shoulder groove area 0.4 times or more of the center groove area, it is possible to ensure drainage performance with a sufficient groove area in the shoulder region TS, and without reducing the shear force on snow. The braking / driving performance on snow can be secured.

Various conditions shown in Table 1 (the number of stud pins driven in the shoulder region TS (the number of shoulder drives), the number of stud pins driven in the center region TC (the number of center driving), and the stud pins in the shoulder region TS based on the center region TC) In the shoulder region TS based on the center region TC, the average protrusion amount of the stud pin in the shoulder region TS (average protrusion amount ratio Sh / Ce), and in the shoulder region TS based on the center region TC The sipe arrangement density (sipe arrangement density ratio Sh / Ce), the average depth of the inclined grooves in the shoulder region TS with respect to the center region TC (average depth difference Sh-Ce), and the center region TC Groove area in the shoulder region TS (groove area ratio S) / According Ce)), to produce a pneumatic tire of Example 5 from the conventional example and the first embodiment.

The tire size (195 / 65R15) of the conventional example and the tires (test tires) of Examples 1 to 5 was 195 / 65R15, and the braking performance on ice and the anti-pinning performance were evaluated for all these test tires. These results are also shown in Table 1.

(Brake performance on ice)
Each test tire was assembled on a 15 × 6 J rim at an air pressure of 230 kPa and mounted on a sedan type vehicle with a displacement of 2000 CC, and the distance from the vehicle to 30 km / h on a icy road was measured. And based on this measurement result, the index evaluation which made the conventional example the reference | standard (100) was performed. This evaluation shows that the higher the index, the higher the braking performance on ice.

(Pin-proof performance)
Each test tire is mounted on a 15 x 6J rim at an air pressure of 230 kPa and mounted on a sedan type vehicle with a displacement of 2000 CC. After running 10,000 km on a general road in Russia with no restrictions on stud tires, The number was confirmed. And based on this confirmation result, the index evaluation which made the conventional example the standard (100) was performed. This evaluation shows that the higher the index, the higher the anti-pinning performance.

According to Table 1, the pneumatic tires of Examples 1 to 5 belonging to the technical scope of the present invention (the number ratio of driving Sh / Ce and the average protrusion amount ratio Sh / Ce are within a predetermined range) It can be seen that the braking performance on ice and the anti-pinning performance are improved in a well-balanced manner with respect to the conventional pneumatic tire that does not belong to the technical scope of the present invention.

The present invention includes the following aspects.

(1) A land portion is defined by a plurality of inclined grooves inclined with respect to the tire circumferential direction, a sipe is provided in at least one of the land portions, and a stud pin is embedded in at least one of the land portions. In the pneumatic tire, the region of 50% of the tire contact width centered on the tire equatorial plane is defined as the center region, and each region up to the contact end is the region outside the center region in the tire width direction. In the case of the shoulder region, the number of stud pins driven in the shoulder region is 1.5 to 2.5 times the number of stud pins driven in the center region, and the studs in the shoulder region The average protruding amount of the pin is 1.2 to 2.0 times the average protruding amount of the stud pin in the center region. The pneumatic tire is.

(2) The pneumatic tire according to (1), wherein the density of the sipes in the shoulder region is 0.4 to 0.8 times that of the sipes in the center region.

(3) The pneumatic tire according to (1) or (2), wherein an average depth of the inclined groove in the shoulder region is 1 to 3 mm smaller than an average depth of the inclined groove in the center region.

(4) The groove area in the shoulder region is 0.4 to 0.8 times the groove area in the center region on the tread development surface in an unloaded state where an internal pressure of −5% to + 5% of the normal internal pressure is applied. The pneumatic tire according to any one of (1) to (3) above.

10 tread surface 12 inclined groove 20 land portion 22 sipe 24 stud pin CL tire equatorial plane E ground contact edge TC center area TS shoulder area

Claims

Air in which a land portion is defined by a plurality of inclined grooves inclined with respect to the tire circumferential direction, a sipe is provided in at least one of the land portions, and a stud pin is embedded in at least one of the land portions In entering tires,
When the area of 50% of the tire contact width centered on the tire equator plane is the center area, and each area up to the contact end is the area outside the center area in the tire width direction,
The number of stud pins driven in the shoulder region is 1.5 to 2.5 times the number of stud pins driven in the center region; and
A pneumatic tire in which an average protrusion amount of the stud pin in the shoulder region is 1.2 to 2.0 times an average protrusion amount of the stud pin in the center region.
2. The pneumatic tire according to claim 1, wherein an arrangement density of the sipes in the shoulder region is 0.4 to 0.8 times an arrangement density of the sipes in the center region.
The pneumatic tire according to claim 1 or 2, wherein an average depth of the inclined groove in the shoulder region is smaller by 1 to 3 mm than an average depth of the inclined groove in the center region.
In the tread development surface in a no-load state in which an internal pressure of −5% to + 5% of the normal internal pressure is applied, the groove area in the shoulder region is 0.4 to 0.8 times the groove area in the center region. The pneumatic tire according to any one of claims 1 to 3.